Printing plate tension hook



Nov. 11, 1958 T, R ZEE'ELL 2,859,693

PRINTING PLATE TENSION HOOK Filed July 20, 1956 INVEN TOR. THEODORE RZ/EBELL United States Patent 2,859,693 PRINTING PLATE TENSION HOOK Theodore R. Ziebell, Milwaukee, Wis., assignor to The Cottrell Company, Westerly, R. I., a corporation of Delaware Application July 20, 1956, Serial No. 599,274

3 Claims. (Cl. 101378) The object of the present invention is to provide a new type printing plate tension hook which contains a floating type plate engaging law beveled on both sides and being adapted for limited vertical movement.

A further object is to provide a plate hook of the character described in which the plate engaging jaw is capable of sufficient movement to permit its use in plate cylinders provided withhelical grooving of slots varying in depth and which is also suitable, in view of its possibilities of vertical extension, to compensate for proper clearance with use in cylinders of different diameters.

A further object is to provide a floating type tension jaw plate hook adaptable for use in both right and left hand cylinder slots.

A still further object is to provide resilient means which engage prelocated detents in the neck of the tension jaw to maintain same in line with the undercut scarf machined in the bottom of the plate adjacent the plate edges.

A practical embodiment of my invention is shown in the accompanying drawing in which Fig. 1 represents a vertical longitudinal section taken on the line II of Fig. 2 looking in the direction of the arrows, showing one of the complementary hook members, the plate and cylinder segments being removed in this view and the horizontally turnable and vertically movable plate engaging form in its retracted position;

Fig. 2 represents a top plan view of a cylinder segment provided with a plate hook according to my invention engaged with the underside of a printing plate;

Fig. 3 represents a vertical longitudinal section showing the other hook member;

Fig. 4 represents a transverse vertical section taken on the line IV-IV of Fig. 3 looking in the direction of the arrows; and

Fig. 5 represents on a difierent scale a side view of an instrument which is used both for actuating the double winged locks and for actuating the propelling mechanism of the plate hook body carrying the hook.

The base to which the printing plates are to be secured is herein shown as a plate cylinder 1 having spaced helical grooves 2 provided with racks 3 along their bottom walls and with overhanging ledges 4, 4 along their side walls, as is usual. The curved printing plates 5 are each shown as having squared marginal edges instead of the usual beveled edges, thus permitting the plates to be positioned in close proximity to one another on their cylinder. Plates 5 also have undercuts 7 extending along their backs adjacent their squared edges 6, which undercuts are arranged to receive the jaw 12 of the plate register hooks to be immediately described.

The elongated body of the register hook is shown as divided longitudinally and vertically into two complementary members 8, 9 removably fastened together by cross screws 10, 11. This divided body is shaped to permit its ready insertion into and removal from its cylinder groove at any desired point along the same, when the two locks carried by the hook are housed within 2,859,693 Patented Nov. 11, 1958 the body in their retracted positions during such insertion.

The double winged lock 13 has a hollow central noncircular bore 15 adapted to receive the lower non-circular shank of the instrument 23 shown in Fig. 5 so that it may be rotated into engagement with the bottom of th overhanging ledges 4 of the cylinder groove.

A second double winged lock 16 has a hollow central non-circular bore 17 extending upwardly to the top of the body and also downwardly into a divided cylindrical opening 19 so that said second double winged lock 16 may also, by use of the non-circular upper shank of instrument 23 of Fig. 5, be turned to contact the underside of the overhanging ledges 4 of the cylinder groove 2.

Means including spring pressed balls 30, 31 located in recesses in the hook body are employed for yieldingly holding said double winged locks in their extended and retracted positions, through the action of their springs 32, 33.

The plate engaging horizontally turnable jaw 12 is beveled on both sides and is adapted for vertical movement in the form shown to the extent of .016 inch. This vertical movement is limited by acollar 37 on the lower end of the shaft 38 which supports an upper collar 39 from which the plate engaging jaw 12 rises vertically. The vertical movement and the radial adjustment of the plate engaging jaw is accomplished by means of a spring 40 and ball 41 located in a diagonal recess in the hook body so as to resiliently bias the lower collar 37 and its jaw 12 upwardly and to cause said ball 41 to engage a prelocated detent denoted by 42 so as to maintain the jaw in its proper position with relation to the undercut groove 7 in the printing plate.

The means for propelling hooks constructed according to my invention along the cylinder recess comprises a horizontally disposed rack engaging gear 20 located in a suitably shaped recess 21 in the hook body, said gear being mounted on shaft 22 having its ends journaled in the vertical side walls of the hook body. A hollow vertically disposed worm 25 is located in one end of recess 22 so as to engage and mesh with the rack engaging gear 20. The lower end of the vertically disposed worm 25 is journaled in the hook body and the upper end of the worm 25 is journaled in the bore of the double winged lock 16.

This hollow Worm 25 is located in axial alignment with the hollow of the second double winged lock 16 and has a non-circular bore 43 adapted for the reception of the lower non-circular shank of the instrument 23.

In operation, the plate hook body is positioned in the cylinder groove so that its jaw will enter the desired undercut groove 7. The upper non-circular shank of the instrument 23 is inserted into the bore 17 of the lock 16 to turn the lock to engage the ledges 4 of the cylinder groove 2. The lower shank of the instrument 23 is inserted into the bore 15 of the lock 13 to turn the lock to also engage the ledges 4. The lower noncircular shank of the hook propelling instrument is then inserted into the bore 43 of the hollow worm 25, to turn same and thereby rotate gear 20, which meshes with the rack 3 in the bottom of the cylinder groove 2 thereby causing the hook body carrying the plate engaging jaw 12 to travel along the cylinder groove in the desired direction, to tension the plate on the cylinder.

It will be seen that by the use of a plurality of plate hooks constructed according to my invention, a printing plate may be held to the cylinder under tension by causing the hooks engaged in the plate grooves to be urged in the desired directions.

It will be noted that even though the plate hooks be used on cylinders of difierent diameters, or in right or left hand cylinder slots, the structure described above permits its adaptation automatically to the cylinders 3 without -the manual-adjustment required of other plate shocks which .do-.not .have the adaptabilityof the present structure.

It will also be understood that the shorter distance between centers ot the flocking-elements eliminates to a --;large-:;extent the .need of plotting the correct heights to non'form ;-to radii ofcylinder'flifierent-ials in .the :under- .flockinggroove. W

; SinCeivariouS changes may 'be made in'the construction, form and arrangernent'of the several parts-without rdepartingfrom the 'spiritandscope of-my invention, I do znotiintend to beilimited to the specific embodiment herein zshOuuranddesoribed except as set forth in the appended ircjlaims.

What I-.claim "is:

- -r1.:;In.-combination, a cylinder having spaced helical ,grooves, at least one printing plate having undercuts italiong :opposite' edges of the plate, and movable plate dension hooks, each zcomprising a body, means for etem'ovably :locking the'body inaselected cylinder groove, qnflans fonzmovingwsaid body along its cylinder groove, an elongated horizontally turnable plate engaging jaw dge adapted for slight vertical movement in the hook -1b0dy and spring means in the .body for biasing the jaw ,upwardly and for holding the said jaw in predetermined horizontal positions whereby the plate is held to the cylinder under tension by the coaction of said jaw and plate undercut.

2. The combination according to claim 1, in which said plate engaging jaw is provided With oppositely beveled side edges for engaging predetermined undercuts at either end of the printing plate.

3. The combination according to claim 1 in which the spring means for biasing the plate engaging jaw upwardly include a spring pressed element engaging coacting dents positioned around the base of the said plate tension hook, the parts being so constructed and arranged that the plate is held to the cylinder under tension.

References Cited in the file of this patent UNITED STATES PATENTS 

